Resarch On Service Robot's Navigation In Part Unknown Environment

The navigation of mobile robot is one of the key and hot issues to successful application of mobile robot systems. Because the working environment of the service robot can't be completely determined, the navigation is more important to resarch for service robot than other robots. This thesis has made a deep and systematic study of the navigation of mobile robot. The following aspects are investigated and discussed:Firstly, the thesis briefly introduces the history of the mobile robotic development and summarizes different research aspects of the robot.Secondly, after analyzed and compared different research development level of foreign and domestic, the thesis proposes a solution to the robot navigation in part unknowen environment. The solution can be divided into two levels:the global path-planning level and the local path-planning level. The main purpose of the first level is to lay out a global path in the static global environment using Ant Colony Algorithm. According to the local environment detected by the sensors, the second level is to avoid obstacles when the unknown-obstacles appear. The second level includes two aspects: obstacle avoidance and path following.MAKLINK Graph is used to build the global working evrionment, which converts the workspace to weighted graph, then Ant Colony Algorithm is used to search the weighted graph and get the global optimal path from the begin position to the goal position.In the second level, this thesis uses VFH* algorithm to guide the robot aviod obstacles during fallowing the global optimal path. VFH* algorithm which introduces the A* search algorithm to the VFH+ algorithm is developed from VFF algorithm. Because of the search process, VFH* algorithm is a pseudo golbal path-planning and can prevent the robot goto the dead zone.Thirdly, the author make two improvents to VFH* algorithm to resolve its shortcomings. After the improvents, VFH* algorithm can be used in dynamic uncertainly envoriment. The algorithm is simulated in Aria platform.Finally, the full text is summarized and predicted the development of mobile robot's navigation.